The present invention relates to a lifting unit for vehicle wheels.
During the fitting and removal of tires onto and from wheels and during an ensuing balancing operation that the worn wheel has to undergo, workers in this field are repeatedly required to lift and lower very heavy wheels, particularly when dealing with industrial vehicles.
More particularly, the most energy-consuming operations are removal of a tire-fitted wheel from the platform of a tire changing machine, transfer of the wheel onto the flanged shaft of a balancing machine, and its subsequent transfer to the vehicle hub for refitting.
Such operations are often carried out at different levels from the ground. This cycle of operations is to be repeated for each wheel to be processed, and thus the overall effort required in a working day is normally considerable.
Moreover, statutory provisions on conditions at the workplace have acknowledged this problem and set a limit to the maximum weight that each operator is required to lift when carrying out the above wheel treating operations.
To comply also with these statutory provisions and meet the increasingly widespread requirements regarding lightening of the physical effort the operators have to endure, various kinds of wheel lifting units have been devised which allow a considerable reduction in overall human energy expenditure to be obtained, thus avoiding manual lifting or transferring of the wheels from one machine to another.
Conventional lifting units essentially comprise a base frame which might be provided with wheels for its movement on the ground, and a turret carried by the base frame along which two overhanging arms can slide so as to converge towards one another or diverge. Such arms are actuated in various ways and provided with clamping elements which are suitable for picking up a wheel from the ground and suitably positioning it on these machines. The movements of the arms are such that the wheels are clamped and at the same time their axes are aligned with the main shaft of a balancing machine onto which the wheel is to be fitted.
When suitably provided with wheels, a lifting unit can also be used for transferring and positioning a worn and balanced wheel onto a respective hub of the vehicle on which it is to be fitted.